Dishwashing machines are known, such as for domestic use, which comprise an electrical heater for heating the dishwashing liquid and for drying the dishes, such heater being generally in the form of a continuous heater, that is to say, it heats fluid passing thereover, as contrasted to heating fluid in a storage tank.
One form of such heater in a dishwashing machine is a bar-like electrical tubular heater, which is disposed in the tank or tub which receives the crockery and the like to be washed. During the dishwashing operation, a part of the washing liquid which is sprayed within the tub for example by distributor arms impinges on the tubular heater so that the washing liquid is heated and the tubular heater is accordingly cooled down. This construction suffers from the disadvantage that dirt and residues from the dishwashing agents remain adhering to and dry on the surface of the heater so that the output of heat from the tubular heater is detrimentally affected. In many cases the heater is masked from the jets or sprays of washing liquid by pieces of crockery so that the tubular heater may suffer from local over-heating, where the washing liquid does not impinge thereon. The crockery is subsequently dried by the radiant heat produced by the tubular heater, so that the drying operation is accordingly irregular; more specifically, items disposed in the region of the heater or in the direct range of radiant heat produced by the heater are heated to a greater degree than items which are further away from the heater or which may be masked by other items in the dishwashing machine. The irregular transfer of heat to the washing liquid and to the crockery in the drying operation results in an increase in the amount of power consumed by the machine.